645010657 has 4 divisors (see below), whose sum is σ = 658734336. Its totient is φ = 631286980.

The previous prime is 645010649. The next prime is 645010669. The reversal of 645010657 is 756010546.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645010657 - 2³ = 645010649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645010607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6861769 + ... + 6861862.

It is an arithmetic number, because the mean of its divisors is an integer number (164683584).

Almost surely, 2^645010657 is an apocalyptic number.

It is an amenable number.

645010657 is a deficient number, since it is larger than the sum of its proper divisors (13723679).

645010657 is a wasteful number, since it uses less digits than its factorization.

645010657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13723678.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 645010657 is about 25397.0600070166. The cubic root of 645010657 is about 864.0170182869.

The spelling of 645010657 in words is "six hundred forty-five million, ten thousand, six hundred fifty-seven".